dplyr可以在多个列或组合键上联接吗？ [英] Can dplyr join on multiple columns or composite key?

问题描述

我意识到 dplyr v3.0允许您加入不同的变量：

I realize that dplyr v3.0 allows you to join on different variables:

left_join（x，y，by = c（ a = b）将 xa 匹配为 yb

但是，是否可以结合使用变量的组合，还是必须事先添加复合键？

However, is it possible to join on a combination of variables or do I have to add a composite key beforehand?

类似这样的东西：

left_join（x，y，by = c（ ac = bd）匹配[ xa 和 xc ]的串联到[ yb 和 yd ]

left_join(x, y, by = c("a c" = "b d") to match the concatenation of [x.a and x.c] to [y.b and y.d]

推荐答案

更新为使用tibble（）

您可以将长度大于1的命名向量传递给通过 left_join（）的参数：

You can pass a named vector of length greater than 1 to the by argument of left_join():

library(dplyr)

d1 <- tibble(
  x = letters[1:3],
  y = LETTERS[1:3],
  a = rnorm(3)
  )

d2 <- tibble(
  x2 = letters[3:1],
  y2 = LETTERS[3:1],
  b = rnorm(3)
  )

left_join(d1, d2, by = c("x" = "x2", "y" = "y2"))

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